Event Notification Report for March 28, 2014

KEOWEE EMERGENCY POWER SYSTEM 13.8kV CABLE MAY NOT COMPLY WITH LICENSING BASIS

"Event: In an NRC Component Design Basis Inspection (CDBI) debrief held at 1300 EDT on March 28, 2014, it was stated that a potential non-compliance and unanalyzed condition exists with respect to the design and installation of the Keowee emergency power system 13.8kV power cables associated with the underground power path. The NRC stated that Duke does not have sufficient documentation to support the station's position that the cables comply with the station's licensing basis. In particular, there are questions related to the station's compliance with IEEE-279-1971. This issue has been documented in Duke's corrective action program.

"Duke has reviewed the design associated with the subject 13.8kV cables and considers the design to be robust. Pending further analysis and/or testing, Duke has made a decision to report this event in accordance with 10 CFR 50.72(b)(3)(ii) as an 'Unanalyzed Condition.' The Oconee NRC Senior Resident Inspector has been notified of the event.

"Initial Safety Significance: An Immediate Determination of Operability has been performed and concluded the existing system design is adequately robust to address circuit faults. The health and safety of the public and station personnel is not impacted by this event.

"Corrective Action(s): Corrective actions are being implemented in accordance with Duke's Corrective Action Program."

ITEMS RELIED ON FOR SAFETY NOT OPERABLE

"It was determined at 1:30PM today (3/28/14) that one of the Items Relied on for Safety (IROFS) associated with the Dry Conversion Process recycle operation was inoperable. Although the second IROFS preventing moderation intrusion to the recycle container continued to operate within its allowable parameters, it alone was not sufficient to meet performance requirements.

"The affected equipment has been shut down and at no time was an unsafe condition present. While this did not result in an unsafe condition, the event is being reported pursuant with the reporting requirements of 10CFR70 Appendix A (b)(2) within 24 hours of discovery.

"Additional corrective actions, extent of condition, and the cause of the failure are being determined."

The licensee will notify NRC Region 2, State of North Carolina Radiation Protection, and New Hanover County Emergency Management.

* * *UPDATE PROVIDED BY SCOTT MURRAY TO JEFF ROTTON AT 1219 EDT ON 03/31/2014 * * *

"After further review, it was determined, at approximately 1125 EDT on 3/31/2014, that the second IROFS [mentioned in the initial report] was not reliable to meet performance requirements. As a result, the report is amended as follows:

"The second IROFS preventing significant moderator intrusion to the recycle container was available, but its reliability could not be confirmed. The control continued to limit significant moderator intrusion and an unsafe condition did not exist. The remaining IROFS was not sufficient to meet performance requirements.

"As a result, the event report is being conservatively amended pursuant with the reporting requirements of 10CFR70 Appendix A (a)(4) within 1 hour of discovery."

The IROFS that was inoperable in the initial report was a process flow moisture probe. The second IROFS that was believed to be available in the initial report but later determined to not be reliable was a set of process control valves used to prevent moderation intrusion to the recycle container.

The licensee will notify NRC Region 2, State of North Carolina Radiation Protection, and New Hanover County Emergency Management.

Notified R2DO (Sykes) and NMSS EO (Rahimi)

FAILURE OF SECONDARY CONTAINMENT DOOR INTERLOCK

"At 1358 [CDT] on March 28, 2014, the Control Room was notified that two Secondary Containment doors (DOOR-62 and DOOR-63) were open at the same lime. This occurred while two employees were entering and exiting the Reactor Building at the exact same time. The time that both doors were open was approximately one (1) second. Secondary Containment differential pressure was maintained throughout the event.

"With both doors open, technical specification surveillance requirement SR 3.6.4.1.3 was not met and Secondary Containment was declared inoperable. Secondary Containment was declared operable after independently verifying at least one Secondary Containment access door was closed.

"The health and safety of the public was maintained as the plant was in a normal condition with no initiating event in progress or signs or elevated radiation levels within Secondary Containment. The NRC Resident Inspector has been notified."

DISCOVERY OF AFTER-THE-FACT EMERGENCY CONDITION -- UNUSUAL EVENT DUE TO SEISMIC EVENT

"On March 28, 2014 at 2110 PDT, station staff felt a minor seismic event, which was verified on the NEIC [National Earthquake Information Center]. On-shift staff reviewed basis documentation and EAL [Emergency Action Levels] classification, and concluded the event was below the threshold to classify the event.

"During post event reviews [conducted on 3/31/2014], it has been determined that those events met the classification criteria for declaration of a Notification of Unusual Event for a seismic event as specified by the Emergency Plan. No emergency situation exists at this time."

Site personnel did perform the steps of the Earthquake abnormal operating procedure even though the entry requirements were not met. There were no plant or equipment issues identified during the site walk downs.

The licensee has notified the NRC Resident Inspector, the State of California and other Local authorities.